Method for Operating a Domestic Appliance, and Domestic Appliance

ABSTRACT

In a method for operating a domestic appliance which can be operated by means of a first energy carrier and by means of a second energy carrier, an optimum energy carrier is determined on the basis of at least one predefinable criterion when a user requests a domestic appliance function.

RELATED APPLICATIONS

This application claims priority to German Patent 10 2010 039 776.8 filed on Aug. 25, 2010, the contents of which are incorporated by reference for all that it teaches.

FIELD OF APPLICATION

The invention relates to a method for operating a domestic appliance, and to a domestic appliance.

BACKGROUND

Domestic appliances which can be operated by means of a first energy carrier, for example electricity, and by means of a second energy carrier, for example gas, are now coming onto the market. Domestic appliances of this kind are also called “dual-fuel” or “bi-fuel” appliances. As an example, a hob can have electrically heated cooking points and gas-heated cooking points and/or an oven can be heated electrically and by means of gas.

SUMMARY

The invention is based on the problem of providing a method for operating dual-fuel domestic appliances of this kind and a dual-fuel domestic appliance, which method and appliance allow the energy carriers to be used in an optimized manner, in particular in an optimized manner in terms of cost.

The invention address this problem in one embodiment virtue of a method as claimed herein and a domestic appliance as claimed herein.

Preferred embodiments are the subject matter of the dependent claims, the wording of the said dependent claims hereby being incorporated in the content of the description by reference.

In a method for operating a domestic appliance which can be operated by means of a first energy carrier and by means of at least a second energy carrier, wherein the domestic appliance especially comprises a first terminal for supplying the first energy carrier and a second terminal for supplying the second energy carrier, an optimum energy carrier is determined on the basis of at least one predefinable criterion when a user requests a domestic appliance function, for example when the user sets the heating power for a hob or when he sets or preselects a desired temperature for an oven.

In one embodiment, the first energy carrier is electricity and the second energy carrier is gas. Examples of other energy carriers include wood pellets, oil and/or solar heat.

The at least one criterion comprises the expected costs which arise when carrying out the requested domestic appliance function using the first energy carrier or the second energy carrier, wherein the expected costs may vary dependent on the time point at which the user requests the domestic appliance function, since the costs of the energy carriers may e.g., vary depending on the time of day. To this end, the quantity of energy carrier which is required to execute the requested domestic appliance function can be determined, for example, first for a respective energy carrier and then the determined quantity of energy carrier can be multiplied by the costs of the energy carrier per unit of energy carrier. The costs of the energy carrier per unit of energy carrier can be permanently stored in the domestic appliance or can be called up for the operating time, for example by means of an intelligent meter and/or via the Internet. If no duration is predefined for the domestic appliance function, the costs of the respective energy carrier relative to a set heating power can be used as a criterion, for example. In this way, the most cost-effective energy carrier can be automatically selected and the domestic appliance function can be executed using this energy carrier.

In another embodiment, the requested domestic appliance function is automatically executed using the energy carrier which is determined as being optimum. Execution can begin immediately or with a delay.

In another embodiment, the costs which are produced by the first energy carrier and the second energy carrier when the requested domestic appliance function is implemented are taken into account in order to calculate the expected costs. In the case of relatively long operating times of the domestic appliance function, for example of a few hours, the current costs of the energy carrier per unit of energy carrier can change while the domestic appliance function is being executed. According to this embodiment, this is taken into account by the time-dependent energy costs being integrated with respect to the duration of the domestic appliance function.

In another embodiment, in order to calculate the expected costs, it is assumed that the requested domestic appliance function is executed without a delay. This is expedient, for example, when the domestic appliance function has to be executed without a delay, for example when preparing a midday meal, this function typically has to be performed without a delay.

If immediate execution is not necessary, the start time which is determined for the requested domestic appliance function can alternatively be one of the kind which leads to a minimum value for the expected costs which arise when carrying out the requested domestic appliance function using the first energy carrier or the second energy carrier. This may be expedient, for example, in the case of a domestic appliance function in the form of drying laundry since, for example, the price of electricity can vary depending on the time of day and therefore it may be expedient in this case to wait until a time of day at which the price of electricity is very low.

The domestic appliance according to the invention is designed to carry out the method and comprises a domestic appliance functional unit having a first heating means, for example an electricity-operated heating means, which can be operated by means of a first energy carrier, and a second heating means, for example a gas-operated heating means, which can be operated by means of a second energy carrier, and an optimization unit which is designed to determine an optimum energy carrier on the basis of at least one predefinable criterion when a user requests a domestic appliance function.

In one embodiment, the domestic appliance functional unit is an oven. In another embodiment the domestic appliance functional unit is a hob. The hob preferably comprises electrically operated cooking points and gas-operated cooking points.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantageous embodiments of the invention are schematically illustrated in the drawing and will be described in the text which follows. In the drawings:

FIG. 1 shows a domestic appliance according to the invention having a hob which can be heated both electrically and by means of gas, and an oven which can be heated both electrically and by means of gas, and

FIG. 2 shows a flowchart of the operation of the hob shown in FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows a dual-fuel domestic appliance 100 according to one embodiment of the invention having a first domestic appliance functional unit in the form of a hob 20 which is heated both electrically and by means of gas, a second domestic appliance functional unit in the form of an oven 30 which is heated both electrically and by means of gas, a network interface 40, a display 50 and a control unit 60, for example a microprocessor control system which controls the operation of the domestic appliance 100. The control unit 60 serves as an optimization unit which is designed to determine the most cost-effective energy carrier for carrying out the domestic appliance function on the basis of a cost criterion when a user requests a domestic appliance function.

The hob 20 comprises, by way of example, an electrically operated cooking point 21 and a gas-operated cooking point 22, with a heating power for the cooking point 21 being set by means of a setting element 21 a, and a heating power for the cooking point 22 being set by means of a setting element 22 a.

A desired temperature of the oven 30 is set by means of a setting element 30 a. It goes without saying that other setting elements (not shown) can be provided.

The operation of the hob 20 shown in FIG. 1 is managed by the control unit 60 and is described by way of example with reference to the flowchart of FIG. 2.

The illustrated program sequence begins with a domestic appliance function being requested by a user (not illustrated) at the start, for example by said user setting a desired heating power for the cooking point 21 or 22 by means of the setting element 21 a or, respectively, 22 a.

In step 210, the control unit 60 first ascertains the current time and the date and the current costs of the energy carrier gas, for example in the form of the cost per cubic metre, and of the energy carrier electricity, for example in the form of the cost per kilowatt hour. These costs can be stored in a memory of the control unit 60 in a date- and time-dependent manner and/or can be checked from a server, for example an intelligent meter, by means of the interface 40.

In step 220, the ascertained energy carrier costs are now compared with one another after being standardized.

The result of the comparison is then displayed on the display 50 in step S30, that is to say an energy carrier which is optimum in terms of cost is determined on the basis of the criterion of energy cost when a user requests a domestic appliance function, and is displayed on the display 50.

If the user operates the setting element 21 a for the electrically heated cooking point and the comparison which was carried out in step 220 showed that electrical operation is more cost-effective, this being checked in a branch step 240, the electric cooking point 21 is electrically heated in step 250. However, if the comparison which was carried out in step 220 showed that gas operation is more cost-effective, the user is provided with a recommendation to change over to gas operation on the display 50 in step 260. The user can then operate the other setting element 22 a in order to use the gas-operated cooking point 22, this being checked in a branch step 270, after which the gas-operated cooking point 22 is activated in step 280. If the user does not perform any other setting operation within a predefined time period, for example 5 seconds, the electric cooking point 21 is used in spite of the higher energy costs.

The operation of the oven 30 will be described in the text which follows without reference to a flowchart. It should be assumed here that the user can use a suitable setting element (not shown) to preselect whether the oven function should be executed immediately, whether the oven function should be executed after a predefinable waiting time, or whether an automatic start time should be calculated on the basis of the criterion of cost-effective operation. Furthermore, the user can specify a baking duration and functions/settings for the manner of heating, for example heat from above, heat from below, etc.

After the user setting operations have been carried out, the control unit 60 then first once again ascertains the current time and the date and the current costs of the energy carrier gas and of the energy carrier electricity.

In order to calculate the costs produced by the first energy carrier and the second energy carrier during execution of the oven function, the energy costs are calculated as a function of the start time specified by the user by the time-dependent energy costs being integrated with respect to the set duration of the oven function. If the user has selected the “automatic start time” option, the start time for the oven function determined is that which leads to a minimum value for the expected energy costs arising when the required domestic appliance function is carried out using electricity or, respectively, gas. In this case, the situation of electricity being comparatively cost-effective during night-time hours can be exploited and/or an excess of solar power can be used when there is a high level of sunshine.

The baking function is then automatically executed using the energy carrier incurring the lowest energy costs.

In the exemplary embodiments shown, the energy costs are the criterion for determining the optimum energy carrier. It goes without saying that other criteria, for example the CO₂ emissions, the time required to carry out the domestic appliance function, the current availability of a respective energy carrier as a function of environmental conditions, for example sun, wind, hydraulic power etc., can be used as an alternative or additional criteria.

The domestic appliance shown comprises a hob and an oven in the illustrated exemplary embodiments. In further embodiments, the domestic appliance can also be a tumble dryer, a washing machine, a dishwasher etc., it being possible to use hot water which is heated by means of the supply of solar heat as an energy carrier in this case. Therefore, in this case, a choice can be made between heating the hot water using electricity and using a hot-water connection which is supplied with solar heat.

In further embodiments, in addition to the shown energy carriers gas and electricity, the invention is also suitable for other types of energy carriers, for example wood pellets, oil, and/or solar heat or solar energy.

In further embodiments, the domestic appliance can also be operated with more than two different energy carriers. Furthermore, a plurality of domestic appliances can, for example, be jointly operated in a network which is optimized in terms of energy. 

1. A method for operating a domestic appliance that can be operated using a first energy carrier in the form of gas and can be operated using a second energy carrier in the form of electricity, wherein an optimum energy carrier is determined on the basis of at least one predefinable criterion when a user requests a domestic appliance function, and wherein the at least one criterion comprises the expected costs arising when carrying out the requested domestic appliance function using the first energy carrier or the second energy carrier.
 2. The method according to claim 1, wherein the requested domestic appliance function is automatically executed using the energy carrier which is determined as being optimum.
 3. The method according to claim 1, wherein the costs produced by the first energy carrier and the second energy carrier when the requested domestic appliance function is implemented are taken into account when calculating the expected costs.
 4. The method according to claim 1, wherein in order to calculate the expected costs, the requested domestic appliance function is assumed to be executed without a delay.
 5. The method according to claim 1, wherein the start time which is determined for the requested domestic appliance function is one of the kind which leads to a minimum value for the expected costs arising when carrying out the requested domestic appliance function using the first energy carrier or the second energy carrier.
 6. A domestic appliance comprising: a domestic appliance functional unit having a first heating means which can be operated by means of a first energy carrier in the form of gas, and a second heating means which can be operated by means of a second energy carrier in the form of electricity; and an optimization unit configured to determine an optimum energy carrier on the basis of at least one predefinable criterion when a user requests a domestic appliance function, wherein the at least one criterion comprises the expected costs arising when carrying out the requested domestic appliance function using the first energy carrier or the second energy carrier.
 7. The domestic appliance according to claim 6, wherein the domestic appliance functional unit is an oven.
 8. The domestic appliance according to claim 6, wherein the domestic appliance functional unit is a hob.
 9. The domestic appliance according to claim 8, wherein the hob comprises electrically operated cooking points and gas-operated cooking points.
 10. A dual-fuel domestic appliance comprising: a domestic appliance functional unit configured be complete a cooking function using either a first energy carrier in the form of gas or a second energy carrier in the form of electricity; a control unit comprising a microprocessor configured to receive user input for executing the cooking function using the domestic appliance functional unit, said user input comprising setting a heating level and a duration of the cooking function. request a first energy carrier cost associated with the first energy carrier and a second energy carrier cost associated with the second energy carrier, determining a first energy cost for completing the cooking function using the first energy carrier and a second energy cost for completing the cooking function using the second energy carrier, and executing the cooking function using first energy carrier when the first energy cost is less than the second energy cost.
 11. The dual-fuel domestic appliance of claim 10 wherein the microprocessor is further configured to: receive input from the user indicating the start time for executing the cooking function is a) to be executed immediately, b) to be executed at an indicated start time, or c) to be executed at a start time determined by the microprocessor based on cost-effective operation.
 12. The dual-fuel domestic appliance of claim 10 further comprising a display, and wherein the microprocessor is further configured to: provide the user with a recommendation to change from the second energy carrier to the first energy carrier, and receive input from the user indicating the first energy carrier is to be used for executing the cooking function.
 13. The dual-fuel domestic appliance of claim 11 further comprising a display, and wherein the microprocessor is further configured to provide the user with a recommendation to change from the first energy carrier to the second energy carrier based on a lower second energy cost compared to the first energy carrier based on the microprocessor determining the first energy cost for completing the cooking function using the first energy carrier at the indicated start time, and the second energy cost for completing the cooking function suing the second energy carrier at the indicated start time.
 14. The dual-fuel domestic appliance of claim 11 wherein the domestic appliance functional unit is an oven and the cooking function is a baking function. 